1. Field of the Invention
The present invention relates to a load balancer, applied to a communication device on which a plurality of network processors having functions such as routing or address searching are mounted, for performing load balance control for frame processes to the respective network processors.
2. Description of the Related Art
In recent years, with an increase in Internet population, an amount of data processed on the Internet rapidly increases. Accordingly, in a communication device such as a router or a switch, loads relating to a routing and/or switching process for a communication frame (packet) such as an IP (Internet Protocol) and the like and a searching process of addresses and the like rapidly increase. For this reason, an improvement in performance of the communication device and an improvement in processing capability are required. Therefore, a network processor, which satisfies a processing capacity required for the communication device must be mounted on the communication device.
However, the processing capacity of the respective network processors cannot always satisfy requirements based on the rapid increase in the Internet communication. In this case, a plurality of network processors having poor processing capacity is mounted on the communication device, and these network processors perform parallel processing. Thus, load balance controls to these network processors must be performed in order to prevent that the loads given to each of the network processors exceed the processing capacity of the respective network processors.
In a conventional technique, when a load balance process is performed to network processors mounted in parallel to each other, transmission routes are distributed on the basis of information such as the addresses or the like of respective frames, and the frames are transmitted to the respective network processors. In addition, a plurality of control parameters used when the route distribution is calculated is set in advance. When the eccentricity (imbalance or disproportion) of the distribution such that the distributed frames are concentrated on a specific network processor cause, the destinations of the frame distribution (distribution pattern) are changed into alternative destinations (alternative distribution pattern) at once by changing the control parameters. In this manner, the eccentricity of the frame distribution is solved.
However, in the conventional technique, the destinations of frame distribution are changed at once. For this reason, before and after the change of the parameters, the destination of distribution of all the frames may be changed. At this time, frames transmitted to routes (network processors), which are not eccentrically distributed, may be transmitted to different routes (network processors) depending on the change of the control parameters. In this case, the continuation of the frames is broken. For this reason, the frames are disconnected, and the frames cannot be correctly communicated. When the dynamic change of the control parameters is frequently performed, the reliability of the communication device may be deteriorated.